Hi Bev,
I looked for a birth with the surname Knight but didn't find the right one.
This is what I found:
Eldred Arnold Mallory
born 9 Dec 1912 in York Ontario
Mother Fern Mallory
She is single and works as a maid.
Is this your grandfather?

Now,I tried looking for soldiers who possibly died in WW1 but without a first name there are many with that surname!
So,do you happen to know if the first name would be Arnold?
Or Eldred?
Talk soon,
Elaine